Today’s post marks a huge milestone for the Masters of Horticulture—200 posts!  To celebrate this accomplishment I am sharing a guest post from noted horticulturist and radio personality C. L. Fornari. (http://www.gardenlady.com).  C. L.  has a new book coming out on May 16 called “Coffee for Roses” (http://amzn.to/1mhXAGq).  In it, she uses her witty writing style and in depth horticultural knowledge to dispel many common horticultural myths that often show up as “fact” in conversation and on Pinterest and FaceBook.  In her excerpt below, she explains when and why you should use epsom salts in your garden (if at all).

Myth # 50 Use Epsom Salt on…

When researching the use of Epsom salt in the garden I was reminded of an old Saturday Night Live sketch about “New Shimmer.” “It’s a floor wax!” the wife, played by Gilda Radner, insists. The husband, Dan Aykroyd, claims, “It’s a dessert topping!” Naturally, the product was both.

Although I haven’t seen Epsom salt recommended as either a floor wax or a dessert topping, it’s been suggested for just about everything else. Through the years, advice columns, books, and now Internet sites have advocated using Epsom salt for tile cleaning, splinter removal, bath soaks, foot treatments, as a hair curling agent, laxative, facial hair remover, curtain stiffening, insecticide, fertilizer, headache cure, sunburn relief, treatment for insect bites, and for creating fake frost on windows.

More about that frost recipe later, but if the same product is recommended for curling hair and removing it, shouldn’t that give a thinking person pause?

Epsom salt was named for a town in Surrey, England, where it was once produced by boiling down mineral-rich spring water. Although the crystalline structure looks rather like table salt, Epsom salt is actually magnesium sulfate and contains 10% magnesium and 6% sulfur.

When I’m asked if Epsom salt should be applied on lawns, around roses, in the vegetable garden, or on houseplants, my reply is always the same. “Is your soil deficient in magnesium?” Most people don’t know; they’ve heard that they can put Epsom salt on plants but they don’t understand what it is or why they might use it.

Let’s get down and dirty about this. Connecting back to the fictional New Shimmer dessert topping for a moment, we might think of soil as we would a recipe for sweets. The ingredients for a tasty dessert need to be in the right proportions to make something delicious. Add too much cinnamon, baking soda or salt and the results would be inedible.

Soil also needs to be kept in balance. It’s a complex community made of minerals, organic matter, fungi, bacteria, other microorganisms, air and water. Too much of any one of those elements can throw everything off so that plants don’t grow as well. Most plants need the magnesium and sulfur that’s in Epsom salt, but unless you’ve tested the dirt you don’t know if your soil already has these elements or not.

So why not just give a plant Epsom salts and see what happens? In response, I think of two popular sayings. The first is Barry Commoner’s second law of ecology: “Everything must go somewhere.” It’s important to remember that products we put in our yards and gardens don’t just vanish. When we put anything into our environment it ultimately ends up somewhere, and that’s often downstream. So, better not to use something in the garden unless we know it’s really needed.

The second phrase that comes to mind is, “If it ain’t broke don’t fix it.” If the plants are growing well, chances are they are happy with the current conditions. Should you see that your plants aren’t doing well, identify the problem first, and then consider all possible solutions. If you suspect the difficulty starts at ground level, have a compete soil test done before taking action.

When you’re unsure if your soils are lacking in any one element, use a complete, organic fertilizer. A balanced fertilizer with all the essentials that plants require is less likely to throw Mother Nature’s recipe off kilter.

Click here to get your copy of “Coffee for Roses”

Epsom Salts Window Frost

Because of Epsom salt’s crystalline nature, it will form frost-like patterns on windows or mirrors when dissolved in liquid and painted on glass. This can be fun for holiday decorating or creating winter scenes.

You’ll see many recipes for Epsom salt frost calling for beer as the liquid, but there seems to be no reason for this; perhaps someone was looking for a way to use up flat beer. The recipe works well with water so your house doesn’t have to smell like a brewery.

½  cup water

½ cup Epsom salt

3 or 4 drops dishwashing detergent (this helps the “frost” stick on the glass)

Bring the water to a boil in a saucepan. Remove from the heat and add the Epsom salt, stirring until it is completely dissolved. Add the drops of detergent and stir again. Let this mixture cool down before using or it will drip excessively, but apply before it starts to crystalize in the pan. Paint or daub it on your glass surface using a paintbrush, cotton ball, micro-fiber cloth, or even your finger.